grail

(usually initial capital letter). Also called Holy Grail. a cup or chalice that in medieval legend was associated with unusual powers, especially the regeneration of life and, later, Christian purity, and was much sought after by medieval knights: identified with the cup used at the Last Supper and given to Joseph of Arimathea.

Holy Grail is anglicized from Middle English Sangreal (Saint graal), grafted awkwardly onto the Celtic Arthurian legends 12c. by Church scribes probably in place of some pagan otherworldly object. It was said to be the cup into which Joseph of Arimathea received the last drops of blood of Christ (according to the writers who picked up the thread of Chrétien de Troyes' "Perceval") or the dish from which Christ ate the Last Supper (Robert de Boron), and ultimately was identified as both (e.g. "þe dische wiþ þe blode," 14c.).